Push and pull with ease

Alongside lifting, holding, carrying and placing, pushing and pulling are some of the activities which are most frequently involved whenever people have to move loads manually. These physically strenuous activities are particularly common in a production and logistics environment, and put employees under significant risk. Depending on the weight of the goods being transported, pushing and pulling can require an enormous amount of strength and can overload muscles, sinews, tendons and joints over time. This can have an effect on the spine, knees, hips and the entire hand-arm-shoulder area.

In order to reduce the risk of injury and disorders, many countries have introduced guidelines restricting the maximum load which can be transported manually. In Germany, this took the form of the Load Handling Regulation (Lastenhandhabungsverordnung). Experts recommend that we don’t use more than 15% of our maximum muscle strength when involved in prolonged activity. The problem is muscle strength varies widely from person to person. It is also extremely difficult to make an accurate assessment of how much strength will be needed to push or pull a load in practice. It is therefore almost impossible to define specific limits which employers and employees can use for guidance.

130 million sick days per year due to musculoskeletal problems

This makes it all the more important to ensure that any work which is carried out repeatedly is made as ergonomic as possible. If you need proof, just look at the statistics related to sick days: According to the annual health report released by the Federal Association of Company Health Insurance Funds [Dachverband der Betriebskrankenkassen] (BKK), musculoskeletal problems are frequently the main cause for being unable to work. According to the Federal Institute for Occupational Safety and Health (BAuA), this issue alone was the reason for 130 million sick days in 2015. This means that tissue-related and musculoskeletal issues cost the German economy around €25 billion, or 0.8% of its GDP. There is therefore a significant financial incentive for companies to improve working conditions.

One reason for these alarming figures is our changing demographics. In many countries, people are working much later in life. Older employees are generally more susceptible to health problems like back or joint pain. Most at risk are employees who work in manufacturing, logistics or construction. These are trades that frequently involve pushing and pulling, and therefore have a heavy impact on the body.

Resistance increases effort

In one way, pushing or pulling loads makes work easier. If something is too heavy to hold or carry, vehicles and transport equipment with wheels or castors are frequently used to reduce the amount of effort required. But moving these around can be tiring as well. This is down to the resistance that you encounter when you set off, roll, change direction or go over an obstacle. The nature of the resistance depends on a number of factors, like the surface you are moving on, the weight of the load and the bearing type and arrangement. But the quality of the wheels that you use is also extremely important.

Starting and rolling resistance is involved whenever you push or pull a load. Force will always be required to get a stationary wheel moving, and also force is still needed to keep it moving consistently. The tread constantly compresses and decompresses whenever you roll a load across the floor, so some energy is wasted due to the internal friction in the tread material. This then results in rolling resistance. Increasing the wheel diameter is one way to reduce rolling resistance, but choosing the optimal tread is also important. It can really make a difference, depending on the geometry, rigidity and elasticity that you go for.

Additional force is required for every change in direction

Using swivel castors increases the swivel resistance for many activities that involve pushing and pulling. This resistance is the reason for the force required to move a castor to the desired position when changing direction. In addition to the factors mentioned above, swivel resistance is also affected by the offset of the castor housing, i.e. the horizontal distance between the rotation axes of the swivel bearing and the wheel. Blickle provides specialised castor brackets with an offset that is designed to minimise swivel resistance.

One example is our new ALB wheel series. Developed specifically for demanding applications in the field of intralogistics, it has a high quality tread with optimised geometry. It is made from reaction-injected polyurethane-elastomer Blickle Besthane. Its rebound elasticity is extremely high, and it is slightly crowned as well, which is a special feature. This reduces the contact area as well as compression and decompression while rolling. The end result is a decrease in rolling resistance of up to 40% compared to other polyurethane wheels. This means that vehicles and transport equipment fitted with the ALB series are much easier to push and pull. With a hardness of 92° Shore A, the Blickle tread has an outstanding dynamic load capacity. This makes the wheels capable of handling higher speeds.

High level of vertical integration and strict test procedures

Our in-house testing laboratory has a specialised station for calculating starting, rolling and swivel resistance. The laboratory is also used for moving over thresholds. These tests are more stringent than standards require. This ensures that our wheels and castors actually meet the necessary requirements.

Our range of wheels and castors makes it much easier to push and pull loads in any situation, and also greatly reduces health risks.